A solid-state imaging element normally contain color filters having patterns of red pixels, green pixels, and blue pixels to detect visible light. In recent years, solid-state imaging element that contains additional pixels that detect infrared light or near infrared light have been proposed.
Near infrared light has wavelengths longer than those of visible light and accordingly it is difficult to scatter. With this feature, near infrared light can be applied to high-precision, three-dimensional measurement and the like. Being invisible to human eyes, furthermore, near infrared light can also be applied to security sensors.
In order to provide a solid-state imaging element has an improved resolution and suffers little color mixing, there is an increasing call for resolution enhancement and pixel film thickness reduction not only in pixel patterns for visible light detection but also in pixel patterns for infrared light/near infrared light detection.
As a coloring composition for a solid-state imaging element which transmits near-infrared light, a coloring composition containing at least one azo type yellow pigment or isoindoline type yellow pigment and a dioxazine type purple pigment has been proposed (see, for example, Patent document 1).
On the other hand, in a black matrix composition for a liquid crystal display (LCD), a technique that uses a lactam compound as a coloring agent to block visible light in the wavelength range of 430 to 650 nm has been proposed (see, for example. Patent document 2).
In addition, that has been proposal of a technique uses a mixture of red, blue, and yellow pigments in the front plate of a touch panel to block visible light in the wavelength range of 400 to 700 nm while transmitting near-infrared light in the wavelength range of 850 to 1200 nm (see, for example, Patent Document 3).